Journal of Engineering

The current practice in Iraq showed that satisfactory sealing of joints for concrete structures is not always achieved. The poor quality of local sealants is usually considered the main cause of such improper performance. The purpose of this work, therefore, is to review and investigate the factors affecting the performance of thermoplastic hot-applied joint sealers which are mostly used in horizontal joints of rigid pavements as shown by the literature reviewed in this study. The impact of different compositions including asphalt cement, reclaimed rubber, mineral filler, fiberglass and, polyvinyl chloride, together with the effect of manufacturing procedures and materials' percentage are studied. Sealant physical properties have been evaluated to include consistency at normal temperatures, resistance to flow at elevated temperatures and, resistance to failure in adhesion or cohesion at very low temperatures. It has been determined that the desired hot-applied sealant can be produced from locally available materials to satisfy the performance-related properties after using optimum contents of asphalt cement (about 45%), reclaimed rubber (about 20%), mineral filler (about 25%), fiberglass (0.1-0.6%), and polyvinylchloride and dioctyl-phthalate (10-15%), in addition to controlling the suitable mixing temperature (170°C) and installing temperature (120-130 °C). This work shall provide a better understanding of the factors influencing the local manufacture of a more durable hot-applied sealant for concrete joints.

This research aims to evaluate the factors affecting building rehabilitation cost
management using the fuzzy analytical hierarchy process (FAHP) model. A literature review,
case studies, consultations with experts, and questionnaires were used to identify and
categorize fifty-seven factors into six categories. The proposed model has considered twenty
factors out of the fifty-seven. The main factor with the highest weight in building
rehabilitation cost management in Iraq is the building characteristics, with a weight of 0.298.
Design and bill of quantities issues follow this with a weight of 0.204. The next factor is
project management Issues with a weight of 0.185. Planning and contract management
factors come next with a weight of 0.150. Safety and environmental factors have a weight of
0.104. The element with the lowest weight is economic and financial factors, with a weight
of 0.058. This order of elements highlights their importance in affecting cost management.
The prioritization within each category is outlined with due consideration to the weights
assigned to the main factors. The significance of required quality standards and site visit to
the building under the design and bill of quantities, while planning and contract
management prioritize project duration and general and specific contract conditions.
Building characteristics prioritize the number of floors in the building and its location,
economic and financial factors emphasize fluctuations in currency exchange rates and labor
costs, and safety and environmental concerns are anchored by health, safety, awareness and
training. Project management emphasizes change orders and a lack of coordination among
team.

Asphaltenes' solubility in crude oils is frequently affected by temperature, pressure, and oil composition changes. This could lead to the precipitation and deposition of asphaltene in various parts of the total production system, which would cause a significant economic impact. Predicting the conditions of asphaltene precipitation will be very useful in two cases. In the first case, without the problem, it will be useful in specifying the optimum operating conditions of oil production operations. In the second case, with the problem occurring, the prediction model will be useful in knowing the deposition areas and their sizes. This study is an extension of the first part, in which the advanced versions of Peng-Robinson (APR78 EOS) and Soave-Redlich-Kwong (ASRK EOS) cubic equations of state and cubic-plus-association equations of state (CPA EOS) were compared in predicting asphaltene precipitation conditions by using Multiflash software. The prediction was made for live crude oil (API gravity = 24˚ API) from an Iraqi oil field at different temperatures. The required data for modeling are fluid compositional analysis, PVT experiment data, and flow assurance data, which were collected from a fluid analysis report. It was noticed that the agreement in prediction was very high between the ASRK EOS and the CPA EOS for all temperature values and diverged from the APR78 EOS model at low temperatures (T = 50 and 40 ˚C). This study demonstrates the impact of selecting the appropriate model on predicting asphaltene precipitation and its influence on future predictions of the asphaltene deposition problem.

The qualities of both fresh and hardened perlite self-compacting concrete are assessed in this study. The self-compacting concrete mix utilized in this investigation included 594 kg/m3 of binder. Four concrete mixes were tested with perlite used in place of some of the coarse aggregate at volumetric ratios of (0, 20, 40, and 50) %. Slump flow, V-funnel, L-Box, and segregation index tests were used to evaluate the properties of fresh concrete. At 56 days after burning, hardened concrete is tested. These tests gauge a material's flexural, splitting, and compressive strengths. According to the data perlite content reduces workability. The percentage of perlite increases causes a considerable decrease in the compressive, flexural, and splitting tensile strengths when compared to the reference mixture. Following their burning at (300, 500, and 700 °C), half of the specimens cooled gradually before being tested, while the other half cooled rapidly. The residual percentages of Compressive strength at 56 days after burning were the most at 50% perlite, with (89.75,65.21, and 42.86) % at 300, 500, and 700 Co, respectively for gradual cooling. The residual percentages of Splitting tensile strength at 56 days after burning for PG50% were (98.85,85.22and 51.31) % at 300, 500, and 700 Co, respectively for gradual cooling.

Moisture induced damage is a prevalent pavement distress commonly observed by road agencies. The damage caused by moisture significantly affects the pavement's lifespan and performance. This research investigated the influence of silica fume (SF) on the susceptibility to moisture. Three concentrations of silica fume were used 3%, 6%, and 9% by weight of the binder. A thermal camera has been used to detect variations in homogeneity in the modified asphalt during the mixing process. The optimal asphalt content was 4.92, 5.02, 5.16, and 5.22 for the control and modified mixtures. The moisture susceptibility was evaluated by measuring the tensile strength ratio (TSR) and index of retained strength (IRS). The thermal images showed that the silica fume particles in the mixture were uniformly distributed, as indicated by the convergence of colors at 160°C. The findings showed that the inclusion of SF at 6% decreased sensitivity to moisture, corresponding to an increase in TSR and IRS of 12.49% and 13%, respectively.

This paper offers a new design, simulation, and trying out a strategy for the Photovoltaic (PV) gadget producing 100 MW· The work explores how different irradiance and PV temperature tiers have an effect on the output power· To enhance the PV system, the proposed work utilizes the Maximum Power Point Tracking (MPPT) technique with a DC-DC boost converter and a 3-phase tie inverter· These components can improve output voltage and convert it into AC electricity for integration into the application grid· The Block Builder tool is taken into consideration a key factor of this work, which enables accurate simulation of various environmental conditions inclusive of a wide range of solar radiation and PV temperature· Consequently, the electric power generated underneath varying parameters can be exactly assessed· In this work, 4 cases are simulated to assess the performance of the proposed system.. The simulation results show that the proposed design gives varying output powers based on changes in solar radiation and PV temperature, which demonstrates the adaptability of the system. In Case 4, the simulation results indicate that when increasing the solar radiation, the energy starts to increase up to 85 MW when solar radiation equals 1000 W/m², which occurs at 3 seconds.

The disposal of concrete debris is in high demand due to the rising amount generated by
demolition activities and the breaking up of concrete goods during transportation and
production. Moreover, it is imperative to preserve natural resources. In recent times, there
has been a growing inclination to utilize these waste materials as a partial replacement for
aggregate. This paper presents the results of a study that examined the utilization of crushed
concrete as aggregates. The crushed concrete was sourced from inspected cube samples of
a road project in Baghdad and subsequently reduced in size till they reached a maximum
dimension of 10 mm. The original reactive powder concrete was used to make crushed
concrete (25% and 100% by volume of the concrete), micro-steel fibers (1% by volume of
the concrete), and fine sand (no more than 1% by volume of the concrete). Study of the
properties of reactive and regular powder concrete, including their compressive and flexural
strengths, as well as their density. When 25% crushed concrete was added to modified
reactive powder concrete, its compressive strength increased by 16.86% and its flexural
strength increased by 10.57%. After seven days and twenty-eight days of testing,
respectively, these enhancements were noted. A 12.04% decrease in compressive strength
at seven days and an 18.2% decrease at 28 days occurred when sand was replaced with
100% broken concrete in the mixture. In a similar vein, flexural strength dropped by 23.5%
after seven days and 20.6% after twenty-eight days.

Water level rise as well as inundation to gypseous soil medium can lead to a substantial loss of volume of the soil, with or without adding load. Macromechanical behavior of gypseous sandy soils using particle image velocimetry (PIV) is yet to be studied, with a particular emphasis on patterns of collapse. These unique patterns have given attention to researchers on deformable soils, but the difficulties of gypseous sandy soil still need to be addressed. Consequently, this study aims to quantify the local-scale displacement fields and patterns of failure of gypseous sand interacting with rigid strip foundations under static stress under comparison, emphasizing wetting due to rising the water table and the dry state using an experimental model and finite element method (FEM). The PIV results showed that the pattern of collapse of the gypseous sandy soil is of the type of punching shear failure, which validated the FEM and these patterns related to soil vertical deformation. Where FEM and PIV results were corresponded well. In addition, the built soil models in FEM are essentially oversimplified representations of the real behavior of the foundation. The outcomes reveal that local scale failure patterns of gypseous soil medium are essential for improving the design of foundations.

In the present work, the impact of metal foam (MF) on the thermal efficiency of a parabolic trough collector (PTC) was experimentally investigated using two types of receivers: one with metal foam insertion (MFI) and one without. Tests were conducted with a 30% filling ratio (FR) of copper foam blocks, consisting of 10 discs, each 45 mm thick, semi-uniformly spaced along the receiver pipe. The copper foam had pore densities of 10–40 PPI and porosities of 0.903 and 0.8983. The experiments carried out under ASHRAE 93 standards involved varying volume flow rates from 0.1 to 0.3 LPM, using water as the heat transfer fluid. The experiments took place in Iraq in May 2024, from 9:00 a.m. to 4:00 p.m., under solar radiation conditions. To ensure data reliability, uncertainty analyses were performed on temperature, solar irradiation, flow rate, and pressure drop. The results indicated that the use of metal foam in the receiver improved collector efficiency, with a notable 16.74% increase at 40 PPI and 0.3 LPM. The highest thermal efficiency was achieved with 40 PPI, which raised the PTC outlet temperature to 58 °C at 0.1 LPM, compared to 53 °C for a without MFI pipe. According to performance evaluation criteria, 10 PPI foam outperforms 40 PPI foam. Compared to the denser 40 PPI, the larger 10 PPI pores improve water flow, reduce resistance, and require less energy to pump the heat transfer fluid (HTF). However, the findings found that while metal foam improves heat transfer efficiency, it increases pressure drop, highlighting the importance of balancing these factors in system design.

Travel Time estimation is largely caused by the stochastic process of arrivals and departures of vehicles and its reliability measurements considering important issues for improving operational efficiency and safety for traffic road networks. The exploration of travel time variability and spatio-temporal analysis of urban streets using the Global Positioning System (GPS) concluded that the mixed land uses and travel congestions caused higher travel times and delays. The accessibility indices were increased by increasing access points and decreasing traffic volumes. The Geographic Information System (GIS) networks can produce a model that overcomes some restrictions of accessibility indices. Different prediction models were developed to capture the main parameters related to travel time. It concluded that delay at signalized intersections in terms of stopping delay was the major parameter affecting the total travel time and total delay time of major urban streets. Travel time estimation algorithms based on speed data loop detectors induced insignificant differences when the study route was a relatively short and slow transition from free state to congestion state. Travel time results are affected by the location of sensors and their sparseness, hence estimation errors increase as detector spacing increases.

The filler in the asphalt mixture is essential since it plays a significant role in toughening and stiffening the asphalt. Changes in filler type can lead the asphalt mixtures to perform satisfactorily during their design life or degrade rapidly when traffic and environmental effects are considered. This study aims to assess the impact of filler types such as limestone dust (LS) and hydrated lime (HL) on Marshall characteristics and moisture damage in asphalt mixtures. Three different percentages of HL were employed in this study to partially replace the LS mineral filler: 1.5, 2.0, and 2.5% by aggregate weight. Furthermore, a control mixture was created with 7% LS by overall aggregate weight for the wearing course layer. The Marshall method was used to obtain the optimal asphalt content and the asphalt mixes' volumetric properties. The optimum asphalt content was used to prepare the asphalt concrete mixes, which were then tested for moisture damage resistance using the indirect tensile strength (ITS) and the index of retained strength (IRS). The findings demonstrate that resistance to moisture damage can be significantly enhanced by partially substituting HL for the LS filler. This was verified by the fact that the optimum increase in the tensile strength ratio (TSR) was 7.29% at 2.5% of HL, and at the same HL percent, the greatest rise in the IRS was 9.81% compared with the control mix.

The physical and social structure of urban residential areas is affected by public open spaces in positive and negative ways. Public spaces serve as the basis for the growth of urban life that promotes physical activities and social relations. The research addressed the problem of lack of knowledge about the mechanisms that contribute to achieving healthy and lively public places according to spatial characteristics. It aimed to develop and improve public places through a more comprehensive knowledge of the effective spatial characteristics that contribute to enhancing the value of public places. The research assumed the existence of a correlation between vital spatial characteristics and healthy environments. For the purpose of testing the hypothesis, the theoretical framework extracted was applied to models of public places in international countries, Such as Canada, Japan, Algeria. The research adopted a qualitative descriptive approach to verify the hypothesis. The results showed that there is a relationship between health and vital environments that helped provide dynamism to the functioning of urban space and can be used as a criterion for measuring the
effectiveness of public places.